The No. 21 seed continued his strong season after returning from a wrist injury that forced him to miss the U.S. Open past year and will play either No. 6 seed Novak Djokovic or unseeded John Millman on Friday.
The 20-year-old Osaka is the first Japanese woman to make the last-four of any Slam since Kimiko Date at Wimbledon in 1996 - a year before she was born.
The Japanese star, who lost to Cilic in his only grand slam final appearance to date four years ago, gained some semblance of revenge as he triumphed 2-6, 6-4, 7-6 (5), 4-6, 6-4 in a match that lasted four hours and eight minutes. "My entire body was shaking, but I was really glad I was able to play well today".
The Californian has dropped just a single set so far at the 2018 edition of the U.S. slam, to Aleksandra Krunic in the third round, and has a 2-0 edge against her upcoming Japanese opponent.
"Well, it definitely means a lot for me, and I always thought if I were to win a Grand Slam, the first one I'd want to win is the US Open, because I have grown up here and, like, then my grandparents can come and watch", she said.
The No. 20 seed moved from Japan to NY at age 3, and her deepest major run is coming at the same tournament she first visited as a child. Osaka was another story who had only met the Belarusian for the first time, knowing only her history on paper but not experiencing it on court.
"It's good to have, you know, home support outside of Japan", he said. Just to see them in person and experience the atmosphere.
She won the Indian Wells Open and made it to the fourth round of the Australian Open.
The crisis soon deepened for Tsurenko, who had needed the best part of three hours on Monday to beat Czech teenager Marketa Vondrousova in a match where she nearly collapsed due to heat exhaustion.
The Indian Wells victor dropped just two games in the entire match and had far too much for her opponent, who had stunned Caroline Wozniacki in the second round. Keys, 23, is a three-time Grand Slam semifinalist and Olympian.